Unfortunately Nexus 5 (One of the popular Nexus Device) is not officially supported to get Android 7.0 Nougat. But Thanks to Santhosh M (Xda developer) who has managed to Port Android 7.0 Nougat AOSP for Nexus 5.
For Now WiFi, RIL, Audio and much more works perfectly, Though there are some bugs which needs to be fixed.
To Install This Custom Build on Your Nexus 5, Just Download the AOSP Build from - Here and Flash the .zip file from any Custom Recovery.
You can head ahead to XDA Forum for more info on AOSP 7.0 Nexus 5.